The present invention relates to a system and method for controlling air conditioning facilities, and a system and method for power management of a computer room. In particular, the invention relates to an air-conditioning facility control system and method for, in a computer room (cooling room) equipped with air-conditioning facilities for air-cooling the computer room in which a large number of information processing units are installed, properly cooling the individual information processing units with the air-conditioning facilities operated in an energy-saving manner, and a power management system and method for power management of the computer room.
In a large-scale computer room typified by a data center, a large number of racks each storing information processing units such as a server and a file device (hereinafter simply referred to as a “unit”) are placed in rows. In addition, the computer room is equipped with a plurality of air conditioners that function as facilities for eliminating heat generated by the individual units (hereinafter referred to as an “air conditioner”). Because most of the units employ an air-cooling system, the air conditioners cool warm discharge air heated by the individual units, and then supplies the individual units with cool air again.
In general, computer rooms often have a double floor structure. Accordingly, cool air generated by the air conditioners is discharged into space between floors. The cool air is then supplied from a large number of air supply openings in proximity to the units. The supplied cool air is taken into each individual unit by a fan that is built into each individual unit. The cool air is then heated by electronic parts, and is increased in temperature, followed by discharging to the outside of the individual units. The discharge air is fed back to the air conditioners through space between the racks and a ceiling, or through exhaust ducts that are specially provided in the computer room and the roof space. In general, the power consumption of the air conditioners ranges from one half to one third of the required cooling capacity (a total calorific value of the units, and a total calorific value of power supply facilities); and the power consumption required for supplying air is about one sixth of the required cooling capacity. Therefore, the power consumption of the whole computer room is about 1.5 times that of the units.
On the other hand, the really required intake temperature of cooling air to be taken into the individual units varies depending on the information processing capability of the units, and an operating ratio that changes every minute. However, for the current computer room, the air conditioners are operated with the discharge air temperature (air supply temperature) of the air conditioners set at a particular value requested by a unit whose required cool air temperature is the lowest. As a result, cool air whose temperature is lower than necessary is taken into most of the units, which leads to a huge amount of energy loss. From the viewpoint of the current tendencies to prevent global warming, and to reduce energy costs, the reduction in energy loss is strongly required.
For the purpose of the reduction in energy loss, venders are making efforts to improve the efficiency of units and that of air conditioners. In addition, when a computer room is designed, units, air conditioners, and air supply openings are located in best place; and the numbers of the units, air conditioners, and air supply openings to be arranged are optimized, whereby cool air is efficiently supplied so that energy saving is achieved. On the other hand, from an operational point of view, the following energy saving methods are proposed and implemented. For example, the power consumption is reduced by one-side shifting of information processing units using a virtual technique. Alternatively, a damper is provided at each individual air supply opening connected between space above floor and space under floor, and the temperature of each individual unit, which changes every minute, is sensed to optimize the amount of supply air from air-conditioning facilities so that energy saving of the air-conditioning facilities is achieved.
Moreover, JP-A-2004-126968 proposes that when discharge air temperature of a certain unit is low, a job moved from another unit is assigned to the unit in question, or a new job is assigned to the unit in question, so that cool air is effectively used to achieve energy saving.
In contrast, JP-A-2006-64283 proposes a control method for controlling air-conditioning facilities although the purpose of the control method is not energy saving. The control method includes the steps of: successively changing set temperature of each air conditioner one by one to determine the extent of influence to which cooling-air generation temperature of each air conditioner influences air temperature of individual units; graphically illustrating the extent of influence; when abnormal temperature is detected in a certain unit, indicating, as guidance, which air conditioner's set temperature should be changed for effective cooling; and controls the set temperature of the air conditioner.
In the prior art disclosed in JP-A-2004-126968, the air temperature in a computer room can be substantially uniformed by performing job scheduling on the basis of temperature information obtained from temperature distribution, and then by controlling the distribution of a load to each individual unit. Thus, energy saving of air conditioning facilities is achieved. However, efficiency characteristics of individual air conditioners constituting air-conditioning facilities are not considered; therefore the individual air conditioners may also be uniformly operated in a partial load mode with low efficiency. In some cases, a larger amount of energy may be consumed.
In addition, in the prior art disclosed in JP-A-2006-64283, the control of air conditioning facilities is merely disclosed as measures to cope with an abnormal state and energy consumption is not taken into consideration. Furthermore, since the guidance displayed on a display unit does not indicate a specific value of the changed set temperature of each air conditioner, the set temperature of each air conditioner must be changed offline according to another guidance (not disclosed).
The present invention has been made to solve the above-described problems, and a primary object of the present invention is to provide an energy saving control method for minimizing the power consumption of air-conditioning facilities while cool air temperature conditions, which are required by individual information processing units disposed in the computer room, are satisfied.
Moreover, another object of the present invention is to provide a system in which the ideal distribution of heat generation in the computer room as viewed from the air conditioning facility side (more specifically, a ratio of a load imposed on each information processing unit) is calculated and cooperation with a monitoring and controlling unit on the information processing unit side is achieved to thereby reduce the power consumption of the computer room as a whole.